Publications by Bixio Rimoldi | EPFL Graph Search

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This paper reports experimental results on self-organizing wireless networks carried by small flying robots. Flying ad hoc networks (FANETs) composed of small unmanned aerial vehicles (UAVs) are flexible, inexpensive and fast to deploy. This makes them a v ...

We study a problem where wireless service providers compete for heterogenous wireless users. The users differ in their utility functions as well as in the perceived quality of service of individual providers. We model the interaction of an arbitrary number ...

Digital video broadcasting (DVB-C2) and other modern communication standards increase diversity by means of a symbol-level interleaver that spans over several codewords. Deinterleaving at the receiver requires a large memory, which has a significant impact ...

For a general class of constant-energy trellis-coded modulation schemes with

2^{\nu}

states, necessary and sufficient conditions to guarantee that a maximum-likelihood sequence estimator can decode each symbol with a fixed delay of

\nu

symbols are derived. Additive white Gaussian noise is assumed. {MSK} is a special case that belongs to the family of modulation schemes with

\nu=1

. It is shown that when these conditions are met, the minimum squared Euclidean distance is upper bounded by

4E_s

, where $

When is uncoded transmission optimal? This paper derives easy-to-check necessary and sufficient conditions that do not require finding the rate-distortion and the capacity-cost functions. We consider the symbol-by-symbol communication of discrete-time memoryless sources across discrete-time memoryless channels, using single-letter coding and decoding. This is an optimal communication system if and only if the channel input cost function and the distortion measure can be written in a form that we explicitly

Different typing devices lead to different typing error patterns. In addition, different persons using the same device have different error patterns. Considering this, we propose and evaluate a spelling algorithm specifically designed for a five-key chordi ...

We study the behavior of users in a classical Additive White Gaussian Noise Multiple Access Channel. We model users as rational entities whose only interest is to maximize their own communication rate, and we model their interaction as a noncooperative one ...

In this paper we examine mobile ad-hoc networks (MANET) composed by unmanned aerial vehicles (UAVs). Due to the high-mobility of the nodes, these networks are very dynamic and the existing routing protocols partly fail to provide a reliable communication.We present Predictive-OLSR an extension to the Optimized Link-State Routing (OLSR) protocol: it enables efficient routing in very dynamic conditions. The key idea is to exploit GPS information to aid the routing protocol. Predictive-OLSR weights the expecte

For a cellular communication network, the loss in up-link bandwidth-efficiency resulting from power equalization is considered. Here power equalization refers to the operation of adjusting the transmit power of mobile units in such a way that the received power is the same for all units whereas bandwidth-efficiency is measured in terms of sum-rate per cell divided by the total system bandwidth. A single-cell system is considered first, and the bandwidth efficiency is determined with and without power equali

We consider source coding with a ﬁdelity criterion, channel coding with a channel input constraint, and the combined problem of reproducing a source across a noisy channel. All three cases face a similar tradeoff between resource and performance, and the o ...

For a general class of constant-energy trellis-coded modulation schemes with 2 ? states, necessary and sufficient conditions to guarantee that a maximum-likelihood sequence estimator can decode each symbol with a fixed delay of ? symbols are derived. Additive white Gaussian noise is assumed. MSK is a special case that belongs to the family of modulation schemes with ? = 1. It is shown that when these conditions are met, the minimum squared Euclidean distance is upper bounded by 4 E s , where E s is the sign

Because of different designs, different text input devices have different error patterns. If we consider these aspects when designing an error correction mechanism, we can obtain significantly lower error rates. In this paper, we propose and evaluate a spelling algorithm specifically designed for a five-key chording keyboard. It is based on the maximum a posteriori probability (MAP) criterion, taking into account a dictionary model and the probability that one character is typed for another. These probabili

This paper describes the implementation and characterisation of a mobile ad-hoc network (MANET) of ultra-light intelligent flying robots. The flying nature of the network makes it suitable to collect or disseminate content in urban areas or challenging ter ...

We address the problem of localizing non-collaborative WiFi devices in a large region. Our main motive is to localize humans by localizing their WiFi devices, e.g. during search-and-rescue operations after a natural disaster. We use an active sensing approach that relies on Unmanned Aerial Vehicles (UAVs) to collect signal-strength measurements at informative locations. The problem is challenging since the measurement is received at arbitrary times and they are received only when the UAV is in close proximi

As different text input devices lead to different typing error patterns, considering the device characteristics when designing an error correction mechanism can lead to significantly improved results. In this paper, we propose and evaluate a spelling algorithm specifically designed for a five-key chording keyboard. It is based on the maximum a posteriori probability criterion, taking into account a dictionary model and the probabilities that one character is typed for another. These probabilities are determ

What makes a source–channel communication system optimal? It is shown that in order to achieve an optimal cost–distortion tradeoff, the source and the channel have to be matched in a probabilistic sense. The match (or lack of it) involves the source distribution, the distortion measure, the channel conditional distribution, and the channel input cost func- tion. Closed-form necessary and sufficient expressions relating the above entities are given. This generalizes both the separa- tion-based approach as we

In this work, we consider the multiple antenna systems in which a large number of antennas occupy a given physical volume, and investigate the behavior of the capacity when increasing the number of antennas. In this regime the assumptions of the standard m ...

It is shown that any point in the capacity region of a Gaussian multiple-access channel is achievable by single-user coding without requiring synchronization among users, provided that each user splits data and signal into two parts. Based on this result, a new multiple-access technique called rate-splitting multiple accessing (RSMA) is proposed. RSMA is a code-division multiple-access scheme for the M-user Gaussian multiple-access channel for which the effort of finding the codes for the M users, of encodi

In a remarkable paper published in 1976, Burna- shev determined the reliability function of variable-length block codes over discrete memoryless channels (DMCs) with feedback. Subsequently, an alternative achievability proof was obtained by Yamamoto and It ...

Bixio Rimoldi

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Dynamic Routing for Flying Ad Hoc Networks

Competition of Wireless Providers for Atomic Users

LLR Compression for BICM Systems Using Large Constellations

Bandwidth-Efficient Constant-Energy Trellis-Coded Modulation Schemes with Prescribed Decoding Delay

To Code, Or Not To Code: On the Optimality of Symbol-by-Symbol Communication

Fine-Tunning a MAP Error Corrections Algorithm for Five-Key Chording Keyboards

Game Theoretic Considerations for the Gaussian Multiple Access Channel

Speed-Aware Routing for UAV Ad-Hoc Networks

Rate Loss Due to Power Equalization in Cellular Communications

Rate Loss Due to Power Equalization in Cellular Communications

On Fidelity Per Unit Cost

Bandwidth-Efficient Constant-Energy Trellis-Coded Modulation Schemes with Prescribed Decoding Delay

MAP-Based Error Correction Mechanism for Five-Key Chording Keyboards

Implementation of a Wireless Mesh Network of Ultra Light MAVs with Dynamic Routing

UAVs using Bayesian Optimization to LocateWiFi Devices

Error Correction Mechanism for Five-Key Chording Keyboards

To code or not to code: lossy source-channel communication revisited

Impact of correlation and coupling on the capacity of MIMO systems

A rate-splitting approach to the Gaussian multiple-access channel

A Simple Converse of Burnashev's Reliability Function